Background and aims <p>Rice, as the staple food for half of the global population, its yield improvement is crucial for ensuring food security. However, excessive application of chemical fertilizers has led to paddy soil degradation and reduced nutrient use efficiency, making it urgent to adopt reasonable improvement measures to achieve high and stable rice yield and sustainable soil utilization.</p> Methods <p>In this study, 8 treatments were set up: Control (no fertilizer); NPK (chemical fertilizer alone); NPK + Sand (chemical fertilizer combined with quartz sand); NPK + Straw (chemical fertilizer combined with rice straw); NPK + Biochar (chemical fertilizer combined with biochar); NPK + Manure (chemical fertilizer combined with organic manure); Manure (organic fertilizer alone); and Integrated (simultaneous application of sand, straw, biochar, and manure with chemical fertilizers). A systematic comparison was made on the effects of various improvement measures on paddy soil physicochemical properties and rice yield, aiming to provide theoretical basis and technical support for paddy soil cultivation and productivity improvement.</p> Results <p>NPK + Manure reduced soil reductive substances, Fe²⁺, and Mn²⁺ to alleviate toxicity, optimized yield components, achieved the highest harvest index, and increased grain N/K accumulation (17.42–19.42%). NPK + Straw improved soil nitrogen, phosphorus, and supply capacity, boosted yields via more panicles, and cut costs. Both outperformed NPK alone, with NPK + Manure as “high-yield/quality” and NPK + Straw as “fertility/efficiency” models.</p> Conclusion <p>Organic–inorganic improvement regulates soil physicochemical properties and redox environment through organic carbon input, optimizes nutrient supply, and achieves increased rice yield and improving soil quality. This provides a scientific basis for sustainable paddy field production and a feasible agronomic strategy to address food security challenges.</p>